With a diverse array of applications, phosphors play a major role in display, diagnostic, sensing, and illumination technologies. A thorough understanding of the underlying science and material properties of the major phosphor materials is essential for bringing these technologies about. In chapters drawn from the second edition of the best-selling Handbook of Phosphors, Fundamentals of Phosphors covers the principles and mechanisms of luminescence in detail and surveys the primary phosphor materials as well as their optical properties. The book addresses cutting-edge developments in phosphor science and technology including oxynitride phosphors and the impact of lanthanide level location on phosphor performance.